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Kalayeh K, Fowlkes JB, Yeras S, Chen A, Daignault-Newton S, Schultz WW, Sack BS. A Comparative Study of Commercially Available Ultrasound Contrast Agents for Sub-harmonic-Aided Pressure Estimation (SHAPE) in a Bladder Phantom. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:1494-1505. [PMID: 39054243 DOI: 10.1016/j.ultrasmedbio.2024.05.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/12/2024] [Revised: 05/14/2024] [Accepted: 05/19/2024] [Indexed: 07/27/2024]
Abstract
OBJECTIVE The goal of this study was to evaluate the performance of different commercial ultrasound contrast microbubbles (MBs) when measuring bladder phantom pressure with sub-harmonic-aided pressure estimation (SHAPE) methodology. We hypothesized that SHAPE performance is dependent on MB formulation. This study aimed to advance the SHAPE application for bladder pressure measurements in humans. METHODS Using a previously designed and built bladder phantom, we tested four different commercial agents: Definity, Lumason, Sonazoid and Optison. A standard clinical cystometrogram (CMG) system was used to infuse a MB-saline mixture into the bladder phantom to measure pressure. Ultrasound imaging was performed using the GE Healthcare LOGIQ E10 scanner. RESULTS All agents showed a predicted inverse linear relationship between change in pressure and SHAPE signal. However, they differ from each other in terms of stability, linear correlation, sensitivity to pressure and error. Generally, Definity and Lumason showed the highest performance during the SHAPE-based bladder phantom pressure assessments. CONCLUSION Our results show that the SHAPE signal decreases as bladder phantom pressures increases, regardless of the agent or CMG phase, suggesting the possibility of using SHAPE for measuring bladder pressure without a catheter. However, the efficacy of SHAPE in measuring pressure varies by MB formulation. These observations support using Lumason and Definity in a human subject feasibility study as we advance toward a catheter-free solution for measuring voiding bladder pressure via SHAPE.
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Affiliation(s)
- Kourosh Kalayeh
- Department of Urology, University of Michigan, Ann Arbor, MI, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, MI, USA; Department of Biomedical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Sophia Yeras
- College of Literature, Science, and the Arts, University of Michigan, Ann Arbor, MI, USA
| | - Amy Chen
- Department of Chemical Engineering, University of Michigan, Ann Arbor, MI, USA
| | | | - William W Schultz
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI, USA
| | - Bryan S Sack
- Department of Urology, University of Michigan, Ann Arbor, MI, USA.
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Zhang L, Dong YF, Chen Y, Li XG, Wang YH, Wang Y, Ge ZT, Wang X, Cai S, Yang X, Zhu QL, Li JC. Impact of Microbubble Degradation and Flow Velocity on Subharmonic-aided Pressure Estimation (SHAPE): An Experimental Investigation. ULTRASOUND IN MEDICINE & BIOLOGY 2024; 50:1020-1027. [PMID: 38594125 DOI: 10.1016/j.ultrasmedbio.2024.03.010] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/10/2024] [Revised: 03/12/2024] [Accepted: 03/21/2024] [Indexed: 04/11/2024]
Abstract
OBJECTIVE This study aimed to investigate the impact of microbubble degradation and flow velocity on Sub-Harmonic Aided Pressure Estimation (SHAPE), and to explore the correlation between subharmonic amplitude and pressure as a single factor. METHODS We develop an open-loop vascular phantom platform system and utilize a commercial ultrasound machine and microbubbles for subharmonic imaging. Subharmonic amplitude was measured continuously at constant pressure and flow velocity to assess the impact of microbubble degradation. Flow velocity was varied within a range of 4-14 cm/s at constant pressure to investigate its relationship to subharmonic amplitude. Furthermore, pressure was varied within a range of 10-110 mm Hg at constant flow velocity to assess its isolated effect on subharmonic amplitude. RESULTS Under constant pressure and flow velocity, subharmonic amplitude exhibited a continuous decrease at an average rate of 0.221 dB/min, signifying ongoing microbubble degradation during the experimental procedures. Subharmonic amplitude demonstrated a positive correlation with flow velocity, with a variation ratio of 0.423 dB/(cm/s). Under controlled conditions of microbubble degradation and flow velocity, a strong negative linear correlation was observed between pressure and subharmonic amplitude across different Mechanical Index (MI) settings (all R2 > 0.90). The sensitivity of SHAPE was determined to be 0.025 dB/mmHg at an MI of 0.04. CONCLUSION The assessment of SHAPE sensitivity is affected by microbubble degradation and flow velocity. Excluding the aforementioned influencing factors, a strong linear negative correlation between pressure and subharmonic amplitude was still evident, albeit with a sensitivity coefficient lower than previously reported values.
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Affiliation(s)
- Li Zhang
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yi-Fan Dong
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Yao Chen
- Department of Ultrasound, GE Healthcare Medical System (China), Shanghai, China
| | - Xiao-Gang Li
- Biobank Facility, National Infrastructures for Translational Medicine, State Key Laboratory of Complex Severe and Rare Diseases, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Ya-Hong Wang
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Ying Wang
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Zhi-Tong Ge
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xin Wang
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Sheng Cai
- Department of Health Medicine, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Xiao Yang
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Qing-Li Zhu
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China
| | - Jian-Chu Li
- Department of Diagnostic Ultrasound, Peking Union Medical College Hospital, Chinese Academy of Medical Science and Peking Union Medical College, Beijing, China.
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Wang P, Tan C, Ji X, Bai J, Yu ACH, Qin P. Sensitivity improvement of subharmonic-based pressure measurement using phospholipid-coated monodisperse microbubbles. ULTRASONICS SONOCHEMISTRY 2024; 104:106830. [PMID: 38432151 PMCID: PMC10920959 DOI: 10.1016/j.ultsonch.2024.106830] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 01/07/2024] [Revised: 02/09/2024] [Accepted: 02/22/2024] [Indexed: 03/05/2024]
Abstract
The use of the subharmonic signal from microbubbles exposed to ultrasound is a promising safe and cost-effective approach for the non-invasive measurement of blood pressure. Achieving a high sensitivity of the subharmonic amplitude to the ambient overpressure is crucial for clinical applications. However, currently used microbubbles have a wide size distribution and diverse shell properties. This causes uncertainty in the response of the subharmonic amplitude to changes in ambient pressure, which limits the sensitivity. The aim of this study was to use monodisperse microbubbles to improve the sensitivity of subharmonic-based pressure measurements. With the same shell materials and gas core, we used a flow-focusing microfluidic chip and a mechanical agitation method to fabricate monodisperse (∼2.45-µm mean radius and 4.7 % polydisperse index) and polydisperse microbubbles (∼1.51-µm mean radius and 48.4 % polydisperse index), respectively. We varied the ultrasound parameters (i.e., the frequency, peak negative pressure (PNP) and pulse length), and found that there was an optimal excitation frequency (2.8 MHz) for achieving maximal subharmonic emission for monodisperse microbubbles, but not for polydisperse microbubbles. Three distinct regimes (occurrence, growth, and saturation) were identified in the response of the subharmonic amplitude to increasing PNP for both monodisperse and polydisperse microbubbles. For the polydisperse microbubbles, the subharmonic amplitude decreased either monotonically or non-monotonically with ambient overpressure, depending on the PNP. By contrast, for the monodisperse microbubbles, there was only a monotonic decrease at all PNPs. The maximum sensitivity (1.18 dB/kPa, R2 = 0.97) of the subharmonic amplitude to ambient overpressure for the monodisperse microbubbles was ∼6.5 times higher than that for the polydisperse microbubbles (0.18 dB/kPa, R2 = 0.88). These results show that monodisperse microbubbles can achieve a more consistent response of the subharmonic signal to changes in ambient overpressure and greatly improve the measurement sensitivity.
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Affiliation(s)
- Pengcheng Wang
- School of Sensing Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Chunjie Tan
- School of Sensing Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China
| | - Xiang Ji
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China
| | - Jingfeng Bai
- School of Biomedical Engineering, Shanghai Jiao Tong University, Shanghai 200030, China.
| | - Alfred C H Yu
- Schlegel Research Institute for Aging, University of Waterloo, Waterloo, ON, N2L3G1, Canada
| | - Peng Qin
- School of Sensing Science and Engineering, Shanghai Jiao Tong University, Shanghai 200240, China.
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Esposito C, Machado P, McDonald ME, Savage MP, Fischman D, Mehrotra P, Cohen IS, Ruggiero N, Walinsky P, Vishnevsky A, Dickie K, Davis M, Forsberg F, Dave JK. Evaluation of Intracardiac Pressures Using Subharmonic-aided Pressure Estimation with Sonazoid Microbubbles. Radiol Cardiothorac Imaging 2024; 6:e230153. [PMID: 38358329 PMCID: PMC10912883 DOI: 10.1148/ryct.230153] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/07/2023] [Revised: 12/13/2023] [Accepted: 01/10/2024] [Indexed: 02/16/2024]
Abstract
Purpose To investigate if the right ventricular (RV) systolic and left ventricular (LV) diastolic pressures can be obtained noninvasively using the subharmonic-aided pressure estimation (SHAPE) technique with Sonazoid microbubbles. Materials and Methods Individuals scheduled for a left and/or right heart catheterization were prospectively enrolled in this institutional review board-approved clinical trial from 2017 to 2020. A standard-of-care catheterization procedure was performed by advancing fluid-filled pressure catheters into the LV and aorta (n = 25) or RV (n = 22), and solid-state high-fidelity pressure catheters into the LV and aorta in a subset of participants (n = 18). Study participants received an infusion of Sonazoid microbubbles (GE HealthCare), and SHAPE data were acquired using a validated interface developed on a SonixTablet (BK Medical) US scanner, synchronously with the pressure catheter data. A conversion factor, derived using cuff-based pressure measurements with a SphygmoCor XCEL PWA (ATCOR) and subharmonic signal from the aorta, was used to convert the subharmonic signal into pressure values. Errors between the pressure measurements obtained using the SHAPE technique and pressure catheter were compared. Results The mean errors in pressure measurements obtained with the SHAPE technique relative to those of the fluid-filled pressure catheter were 1.6 mm Hg ± 1.5 [SD] (P = .85), 8.4 mm Hg ± 6.2 (P = .04), and 7.4 mm Hg ± 5.7 (P = .09) for RV systolic, LV minimum diastolic, and LV end-diastolic pressures, respectively. Relative to the measurements with the solid-state high-fidelity pressure catheter, the mean errors in LV minimum diastolic and LV end-diastolic pressures were 7.2 mm Hg ± 4.5 and 6.8 mm Hg ± 3.3 (P ≥ .44), respectively. Conclusion These results indicate that SHAPE with Sonazoid may have the potential to provide clinically relevant RV systolic and LV diastolic pressures. Keywords: Ultrasound-Contrast, Cardiac, Aorta, Left Ventricle, Right Ventricle ClinicalTrials.gov registration no.: NCT03245255 © RSNA, 2024.
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Affiliation(s)
- Cara Esposito
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Priscilla Machado
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Maureen E. McDonald
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Michael P. Savage
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - David Fischman
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Praveen Mehrotra
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Ira S. Cohen
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Nicholas Ruggiero
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Paul Walinsky
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Alec Vishnevsky
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Kristopher Dickie
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Marguerite Davis
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Flemming Forsberg
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
| | - Jaydev K. Dave
- From the Departments of Radiology (C.E., P.M., F.F., J.K.D.), Medical
Imaging and Radiation Sciences (M.E.M.), and Medicine (M.P.S., D.F., P.M.,
I.S.C., N.R., P.W., A.V., M.D.), Thomas Jefferson University, Philadelphia, Pa;
Clarius Mobile Health, Vancouver, Canada (K.D.); and Department of Radiology,
Mayo Clinic, Rochester, Minn (J.K.D)
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Li R, Zhang Y, Zheng S, Zhang W, Du K, He W, Zhang W. Biomechanical characteristics in the carotid artery: Noninvasive assessment using subharmonic emissions from microbubbles. Med Phys 2023; 50:6857-6863. [PMID: 37337456 DOI: 10.1002/mp.16542] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/28/2023] [Revised: 05/03/2023] [Accepted: 05/08/2023] [Indexed: 06/21/2023] Open
Abstract
BACKGROUND Stroke is closely related to carotid atherosclerotic plaques, which tend to occur in specific parts of the arteries, especially at the bifurcations, and are considered to be caused by biomechanical factors. Quantitative analysis of hemodynamic stress characteristics of the carotid sinus in vivo provides a mechanical basis for the development of atherosclerotic plaque in the carotid sinus. Previous studies found that ultrasound (US) contrast agent microbubbles would vibrate nonlinearly under the excitation of sound pressure, generating subharmonics (transmission fundamental frequency, i.e., f0 and subharmonic frequency at f0 /2), which have the highest sensitivity to pressure changes and exhibit an inverse linear relationship with environmental pressure. PURPOSE This study employed subharmonic aided pressure estimation (SHAPE) technology to reflect carotid artery hydrodynamic characteristics in the carotid lumen. METHODS From May 2021 to December 2021, this prospective study reviewed a total of 26 normal carotid arteries of 13 participants, all of whom received bilateral carotid artery routine US and SHAPE US examinations. During this study, the lumen of the bilateral distal segment of the common carotid artery (Distal-CCA), carotid artery bifurcation (CAB), and carotid bulb (CB) were scanned section by section from bottom to top in longitudinal and transverse sections. Subsequently, the subharmonic amplitudes in the lumen of normal carotid arteries were collected and analyzed. RESULTS This study found that the amplitude of subharmonic amplitude in the carotid was distributed unevenly, with the amplitudes of subharmonic at the CAB being higher. Specifically, the subharmonic gradient of the carotid artery bifurcation apex plane was maximum (9.72 ± 4.31 dB), while the average subharmonic amplitude of the outer lateral layer of the carotid artery was higher (-56.40 ± 6.31 dB) (p < 0.001). CONCLUSION The SHAPE technique is capable of indirectly reflecting the pressure changes of vascular system tissues, which may provide a new monitoring method for evaluating mechanical characteristics obviating invasion.
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Affiliation(s)
- Rui Li
- Department of Ultrasound, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Yukang Zhang
- Department of Ultrasound, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Shuai Zheng
- Department of Ultrasound, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wenkai Zhang
- Department of Ultrasound, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Kai Du
- Department of Ultrasound, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wen He
- Department of Ultrasound, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
| | - Wei Zhang
- Department of Ultrasound, Beijing Tiantan Hospital, Capital Medical University, Beijing, China
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Azami RH, Forsberg F, Eisenbrey JR, Sarkar K. Ambient Pressure Sensitivity of the Subharmonic Response of Coated Microbubbles: Effects of Acoustic Excitation Parameters. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:1550-1560. [PMID: 37100673 PMCID: PMC10306329 DOI: 10.1016/j.ultrasmedbio.2023.02.019] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 11/11/2022] [Revised: 01/20/2023] [Accepted: 02/27/2023] [Indexed: 05/17/2023]
Abstract
OBJECTIVE The sensitivity of the acoustic response of microbubbles, specifically a strong correlation between their subharmonic response and the ambient pressure, has motivated development of a non-invasive subharmonic-aided pressure estimation (SHAPE) method. However, this correlation has previously been found to vary depending on the microbubble type, the acoustic excitation and the hydrostatic pressure range. In this study, the ambient pressure sensitivity of microbubble response was investigated. METHODS The fundamental, subharmonic, second harmonic and ultraharmonic responses from an in-house lipid-coated microbubble were measured for excitations with peak negative pressures (PNPs) of 50-700 kPa and frequencies of 2, 3 and 4 MHz in the ambient overpressure range 0-25 kPa (0-187 mmHg) in an in vitro setup. RESULTS The subharmonic response typically has three stages-occurrence, growth and saturation-with increasing excitation PNP. We find distinct decreasing and increasing variations of the subharmonic signal with overpressure that are closely related to the threshold of subharmonic generation in a lipid-shelled microbubble. Above the excitation threshold, that is, in the growth-saturation phase, subharmonic signals decreased linearly with slopes as high as -0.56 dB/kPa with ambient pressure increase; below the threshold excitation (at atmospheric pressure), increasing overpressure triggers subharmonic generation, indicating a lowering of subharmonic threshold, and therefore leads to an increase in subharmonic with overpressure, the maximum enhancement being ∼11 dB for 15 kPa overpressure at 2 MHz and 100 kPa PNP. CONCLUSION This study indicates the possible development of novel and improved SHAPE methodologies.
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Affiliation(s)
- Roozbeh H Azami
- Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC, USA
| | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA, USA
| | - John R Eisenbrey
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA, USA
| | - Kausik Sarkar
- Department of Mechanical and Aerospace Engineering, George Washington University, Washington, DC, USA.
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Kalayeh K, Fowlkes JB, Chen A, Yeras S, Fabiilli ML, Claflin J, Daignault-Newton S, Schultz WW, Sack BS. Pressure Measurement in a Bladder Phantom Using Contrast-Enhanced Ultrasonography-A Path to a Catheter-Free Voiding Cystometrogram. Invest Radiol 2023; 58:181-189. [PMID: 36070543 DOI: 10.1097/rli.0000000000000919] [Citation(s) in RCA: 4] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/26/2022]
Abstract
OBJECTIVES The long-term goal of this study is to investigate the efficacy of a novel, ultrasound-based technique called subharmonic-aided pressure estimation (SHAPE) to measure bladder pressure as a part of a cystometrogram (CMG) in a urodynamic test (ie, pressure-flow study). SHAPE is based on the principle that subharmonic emissions from ultrasound contrast microbubbles (MBs) decrease linearly with an increase in ambient pressure. We hypothesize that, using the SHAPE technique, we can measure voiding bladder pressure catheter-free. This is of importance because the CMG catheter, due to its space-occupying property and non-physiological effects, can undermine the reliability of the test during voiding and cause misdiagnosis. In this study, we tested this hypothesis and optimized the protocol in a controlled benchtop environment. MATERIALS AND METHODS A bladder phantom was designed and built, capable of simulating clinically relevant bladder pressures. Laboratory-made lipid-shelled MBs (similar in composition to the commercial agent, DEFINITY) was diluted in 0.9% normal saline and infused into the bladder phantom using the CMG infusion system. A typical simulated CMG consists of 1 filling and 4 post-filling events. During CMG events, the bladder phantom is pressurized multiple times at different clinically relevant levels (small, medium, and large) to simulate bladder pressures. Simultaneous with pressurization, MB subharmonic signal was acquired. For each event, the change in MB subharmonic amplitude was correlated linearly with the change in bladder phantom pressure, and the SHAPE conversion factor (slope of the linear fit) was determined. In doing so, a specific signal processing technique (based on a small temporal window) was used to account for time-decay of MB subharmonic signal during a simulated CMG. RESULTS A strong inverse linear relationship was found to exist between SHAPE and bladder phantom pressures for each of the CMG filling and post-filling events ( r2> 0.9, root mean square error < 0.3 dB, standard error <0.01 dB, and P < 0.001). SHAPE showed a transient behavior in measuring bladder phantom pressure. The SHAPE conversion factor (in dB/cm H 2 O) varied between filling and post-filling events, as well as by post-filling time. The magnitude of the SHAPE conversion factor tended to increase immediately after filling and then decreases with time. CONCLUSIONS Microbubble subharmonic emission is an excellent indicator of bladder phantom pressure variation. The strong correlation between SHAPE signal and bladder phantom pressure is indicative of the applicability of this method in measuring bladder pressure during a CMG. Our results suggest that different SHAPE conversion factors may be needed for different events during a CMG (ie, at different time points of a CMG). These findings will help us better protocolize this method for introduction into human subjects and allow us to take the next step toward developing a catheter-free voiding CMG using SHAPE.
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Affiliation(s)
| | | | - Amy Chen
- Department of Biomedical Engineering
| | | | | | | | | | - William W Schultz
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, MI
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Esposito C, Machado P, McDonald ME, Savage MP, Fischman D, Mehrotra P, Cohen IS, Ruggiero N, Walinsky P, Vishnevsky A, Dickie K, Davis M, Forsberg F, Dave JK. Noninvasive Evaluation of Cardiac Chamber Pressures Using Subharmonic-Aided Pressure Estimation With Definity Microbubbles. JACC Cardiovasc Imaging 2023; 16:224-235. [PMID: 36648035 DOI: 10.1016/j.jcmg.2022.09.013] [Citation(s) in RCA: 7] [Impact Index Per Article: 7.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/11/2022] [Revised: 08/04/2022] [Accepted: 09/16/2022] [Indexed: 11/17/2022]
Abstract
BACKGROUND Noninvasive and accurate assessment of intracardiac pressures has remained an elusive goal of noninvasive cardiac imaging. OBJECTIVES The purpose of this study was to investigate if errors in intracardiac pressures obtained noninvasively using contrast microbubbles and the subharmonic-aided pressure estimation (SHAPE) technique are <5 mm Hg. METHODS In a nonrandomized institutional review board-approved clinical trial (NCT03243942), patients scheduled for a left-sided and/or right-sided heart catheterization procedure and providing written informed consent were included. A standard-of-care catheterization procedure was performed advancing clinically used pressure catheters into the left and/or right ventricles and/or the aorta. After pressure catheter placement, patients received an infusion of Definity microbubbles (n = 56; 2 vials diluted in 50 mL of saline; infusion rate: 4-10 mL/min) (Lantheus Medical Imaging). Then SHAPE data was acquired using a validated interface developed on a SonixTablet scanner (BK Medical Systems) synchronously with the pressure catheter data. A conversion factor (mm Hg/dB) was derived from SHAPE data and measurements with a SphygmoCor XCEL PWA device (ATCOR Medical) and was combined with SHAPE data from the left and/or the right ventricles to obtain clinically relevant systolic and diastolic ventricular pressures. RESULTS The mean value of absolute errors for left ventricular minimum and end diastolic pressures were 2.9 ± 2.0 and 1.7 ± 1.2 mm Hg (n = 26), respectively, and for right ventricular systolic pressures was 2.2 ± 1.5 mm Hg (n = 11). Two adverse events occurred during Definity infusion; both were resolved. CONCLUSIONS These results indicate that the SHAPE technique with Definity microbubbles is encouragingly efficacious for obtaining intracardiac pressures noninvasively and accurately. (Noninvasive, Subharmonic Intra-Cardiac Pressure Measurement; NCT03243942).
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Affiliation(s)
- Cara Esposito
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Priscilla Machado
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Maureen E McDonald
- Medical Imaging and Radiation Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael P Savage
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - David Fischman
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Praveen Mehrotra
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ira S Cohen
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Nicholas Ruggiero
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paul Walinsky
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Alec Vishnevsky
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | | | - Marguerite Davis
- Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Jaydev K Dave
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
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Lu H, Xu G, Wang Y, Yang H, Li D, Huang L, Su M, Li C, Qiu W, Mao Y, Yu W, Li F. Correlation Between Portal Vein Pressure and Subharmonic Scattering Signals From SonoVue Microbubbles in Canines. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:203-211. [PMID: 36266141 DOI: 10.1016/j.ultrasmedbio.2022.08.014] [Citation(s) in RCA: 1] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/20/2021] [Revised: 08/25/2022] [Accepted: 08/26/2022] [Indexed: 06/16/2023]
Abstract
The current gold standard for the clinical diagnosis of portal hypertension (PH) is an invasive and indirect estimation of portal vein pressure (PVP). Therefore, the need for a non-invasive PVP measurement method is urgent. Subharmonic scattering of ultrasound contrast agent (UCA) microbubbles is under investigation in clinical research as a pressure indicator. However, the driving acoustic pressure must be optimized to improve the ambient pressure sensitivity of the subharmonic amplitude for different UCAs. In this study, for the first time, we obtained the relationship between the PVP and the amplitude of the subharmonic signal scattered from SonoVue microbubbles by using two canines to build the PH model. The results revealed a desirable linear correlation between the subharmonic amplitude and PVP (<20 mmHg) at the incident acoustic pressure of 453 kPa (r = -0.910, p < 0.005; sensitivity: -2.003 dB/mmHg); this was one order of magnitude higher in sensitivity than that of the in vitro case with a detectable pressure variation of approximately 1 mmHg. This indicates the feasibility of using UCA microbubbles to accurately measure low ambient pressures in vivo and further exhibits the potential of the method for non-invasive pressure estimation in clinical applications.
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Affiliation(s)
- Huimin Lu
- Department of Critical Care Medicine, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing, China; Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Gang Xu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; Department of Liver Surgery, Peking Union Medical College (PUMC) Hospital, PUMC and Chinese Academy of Medical Sciences, Beijing, China; Department of Liver Surgery and Liver Transplantation Center, West China Hospital of Sichuan University, Chengdu, China
| | - Yun Wang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China; Department of Ultrasound, Sun Yat-Sen University Cancer Center, State Key Laboratory of Oncology in South China, Collaborative Innovation Center for Cancer Medicine, Guangzhou, China
| | - Huayu Yang
- Department of Liver Surgery, Peking Union Medical College (PUMC) Hospital, PUMC and Chinese Academy of Medical Sciences, Beijing, China
| | - Deyu Li
- Key Laboratory for Biomechanics and Mechanobiology of the Ministry of Education, Beijing Advanced Innovation Centre for Biomedical Engineering, School of Biological Science and Medical Engineering, Beihang University, Beijing, China
| | - Laixin Huang
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Min Su
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Changcan Li
- Department of Liver Surgery, Peking Union Medical College (PUMC) Hospital, PUMC and Chinese Academy of Medical Sciences, Beijing, China
| | - Weibao Qiu
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China
| | - Yilei Mao
- Department of Liver Surgery, Peking Union Medical College (PUMC) Hospital, PUMC and Chinese Academy of Medical Sciences, Beijing, China.
| | - Wenkui Yu
- Department of Critical Care Medicine, Nanjing Drum Tower Hospital, Affiliated Hospital of Nanjing University Medical School, Nanjing, China.
| | - Fei Li
- Paul C. Lauterbur Research Center for Biomedical Imaging, Shenzhen Institutes of Advanced Technology, Chinese Academy of Sciences, Shenzhen, China.
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10
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Kalayeh K, Fowlkes JB, Claflin J, Fabiilli ML, Schultz WW, Sack BS. Ultrasound Contrast Stability for Urinary Bladder Pressure Measurement. ULTRASOUND IN MEDICINE & BIOLOGY 2023; 49:136-151. [PMID: 36244919 DOI: 10.1016/j.ultrasmedbio.2022.08.008] [Citation(s) in RCA: 5] [Impact Index Per Article: 5.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 04/05/2022] [Revised: 06/13/2022] [Accepted: 08/08/2022] [Indexed: 06/16/2023]
Abstract
The goal of this study was to evaluate ultrasound contrast microbubbles (MB) stability during a typical cystometrogram (CMG) for bladder pressure measurement application using the subharmonic-aided pressure estimation technique. A detailed study of MB stability was required given two unique characteristics of this application: first, bulk infusion of MBs into the bladder through the CMG infusion system, and second, duration of a typical CMG which may last up to 30 min. To do so, a series of size measurement and contrast-enhanced ultrasound imaging studies under different conditions were performed and the effects of variables that we hypothesized have an effect on MB stability, namely, i) IV bag air headspace, ii) MB dilution factor, and iii) CMG infusion system were investigated. The results verified that air volume in intravenous (IV) bag headspace was not enough to have a significant effect on MB stability during a CMG. We also showed that higher MB dosage results in a more stable condition. Finally, the results indicated that the CMG infusion system adversely affects MB stability. In summary, to ensure MB stability during the entire duration of a CMG, lower filling rates (limited by estimated bladder capacity in clinical applications) and/or higher MB dosage (limited by FDA regulations and shadowing artifact) and/or the consideration of alternative catheter design may be needed.
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Affiliation(s)
- Kourosh Kalayeh
- Department of Urology, University of Michigan, Ann Arbor, Michigan, USA
| | - J Brian Fowlkes
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA.
| | - Jake Claflin
- Department of Urology, University of Michigan, Ann Arbor, Michigan, USA
| | - Mario L Fabiilli
- Department of Radiology, University of Michigan, Ann Arbor, Michigan, USA
| | - William W Schultz
- Department of Mechanical Engineering, University of Michigan, Ann Arbor, Michigan, USA
| | - Bryan S Sack
- Department of Urology, University of Michigan, Ann Arbor, Michigan, USA
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11
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Esposito C, Machado P, Cohen IS, Mehrotra P, Savage M, Fischman D, Davis M, Ruggiero N, Walinsky P, McDonald ME, Dickie K, Forsberg F, Dave JK. Comparing Central Aortic Pressures Obtained Using a SphygmoCor Device to Pressures Obtained Using a Pressure Catheter. Am J Hypertens 2022; 35:397-406. [PMID: 35079778 PMCID: PMC9088843 DOI: 10.1093/ajh/hpac010] [Citation(s) in RCA: 7] [Impact Index Per Article: 3.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2021] [Revised: 01/11/2022] [Accepted: 01/24/2022] [Indexed: 01/27/2023] Open
Abstract
BACKGROUND This study compared aortic pressures estimated using a SphygmoCor XCEL PWA device (ATCOR, Naperville, IL) noninvasively with aortic pressures obtained using pressure catheters during catheterization procedures and analyzed the impact of a linear-fit function on the estimated pressure values. METHODS One hundred and thirty-six patients scheduled for cardiac catheterization procedure were enrolled in IRB approved studies. Catheterization procedures were performed according to standard-of-care to acquire aortic pressure measurements. Immediately after the catheterization procedure with the pressure catheters removed, while the patients were still in the catheterization laboratory, central aortic pressures were estimated with the SphygmoCor device (using its inbuilt transfer function). The error between measured and estimated aortic pressures was evaluated using Bland-Altman analysis (n = 93). A linear-fit was performed between the measured and estimated pressures, and using the linear equation the error measurements were repeated. A bootstrap analysis was performed to test the generalizability of the linear-fit function. In a subset of cases (n = 13), central aortic pressure values were also obtained using solid-state high-fidelity catheters (Millar, Houston, TX), and the error measurements were repeated. RESULTS The magnitude of errors between the measured and estimated aortic pressures (mean errors >6.4 mm Hg; mean errors >8.0 mm Hg in the subset) were reduced to less than 1 mm Hg after using the linear-fit function derived in this study. CONCLUSIONS For the population examined in this study, the SphygmoCor data must be used with the linear-fit function to obtain aortic pressures that are comparable to the measurements obtained using pressure catheters. CLINICAL TRIALS REGISTRATION Trial Numbers NCT03243942 and NCT03245255.
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Affiliation(s)
- Cara Esposito
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Priscilla Machado
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ira S Cohen
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Praveen Mehrotra
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael Savage
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - David Fischman
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Marguerite Davis
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Nicholas Ruggiero
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paul Walinsky
- Division of Cardiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Maureen E McDonald
- Department of Medical Imaging and Radiation Sciences, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | | | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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12
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Gupta I, Fenkel JM, Eisenbrey JR, Machado P, Stanczak M, Wessner CE, Shaw CM, Miller C, Soulen MC, Wallace K, Forsberg F. A Noninvasive Ultrasound Based Technique to Identify Treatment Responders in Patients with Portal Hypertension. Acad Radiol 2021; 28 Suppl 1:S128-S137. [PMID: 33341374 DOI: 10.1016/j.acra.2020.11.023] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2020] [Revised: 11/18/2020] [Accepted: 11/28/2020] [Indexed: 02/07/2023]
Abstract
RATIONALE AND OBJECTIVE Subharmonic aided pressure estimation (SHAPE) is based on the inverse relationship between the subharmonic amplitude of ultrasound contrast microbubbles and ambient pressure. The aim of this study was to verify if SHAPE can accurately monitor disease progression in patients identified with portal hypertension. MATERIALS & METHODS A modified Logiq 9 scanner with a 4C curvi-linear probe (GE, Waukesha, WI) was used to acquire SHAPE data (transmitting and receiving at 2.5 and 1.25 MHz, respectively) using Sonazoid (GE Healthcare, Oslo, Norway; FDA IND 124,465). Twenty-one (median age 59 years; 12 Males) of the 178 patients enrolled in this institutional review board approved study (14F.113) were identified as having clinically significant portal hypertension based on their hepatic venous pressure gradient results ≥ 10 mmHg. Repeat SHAPE examinations were done every 6.2 months. Liver function tests and clinical indicators were used to establish treatment response. RESULTS Of the 21 portal hypertensive subjects, 11 had successful follow up scans with an average follow up time of 6.2 months. There was a significantly larger SHAPE signal reduction in the group who were classified as treatment responders (n = 10; -4.01±3.61 dB) compared to the single nonresponder (2.33 dB; p < 0.001). Results for responders matched the corresponding clinical outcomes of improved model for end stage liver disease (MELD) scores, improvement in underlying cause of portal hypertension, improved liver function tests and reduced ascites. CONCLUSION SHAPE can potentially monitor disease progression in portal hypertensive patients and hence, may help clinicians in patient management. A larger study would further validate this claim.
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13
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Esposito C, Dickie K, Forsberg F, Dave JK. Developing an Interface and Investigating Optimal Parameters for Real-Time Intracardiac Subharmonic-Aided Pressure Estimation. IEEE TRANSACTIONS ON ULTRASONICS, FERROELECTRICS, AND FREQUENCY CONTROL 2021; 68:579-585. [PMID: 32784134 PMCID: PMC7983258 DOI: 10.1109/tuffc.2020.3016264] [Citation(s) in RCA: 8] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/11/2023]
Abstract
Thisstudy focuses on evaluating the real-time functionality of a customized interface and investigating the optimal parameters for intracardiac subharmonic-aided pressure estimation (SHAPE) utilizing Definity (Lantheus Medical Imaging Inc., North Billerica, MA, USA) and Sonazoid (GE Healthcare, Oslo, Norway) microbubbles. Pressure measurements within the chambers of the heart yield critical information for managing cardiovascular diseases. An alternative to current, invasive, clinical cardiac catheterization procedures is utilizing ultrasound contrast agents and SHAPE to noninvasively estimate intracardiac pressures. Therefore, this work developed a customized interface (on a SonixTablet, BK Ultrasound, Peabody, MA, USA) for real-time intracardiac SHAPE. In vitro, a Doppler flow phantom was utilized to mimic the dynamic pressure changes within the heart. Definity (15.0- [Formula: see text] microspheres corresponding to 0.1-0.15 mL) and Sonazoid (GE Healthcare; 0.4- [Formula: see text] microspheres corresponding to 0.05-0.15 mL) microbubbles were used. Data were acquired for varying transmit frequencies (2.5-4.0 MHz), and pulse shaping options (square wave and chirp down) to determine optimal transmit parameters. Simultaneously obtained radio frequency data and ambient pressure data were compared. For Definity, the chirp down pulse at 3.0 MHz yielded the highest correlation ( r = - 0.77 ± 0.2 ) between SHAPE and pressure catheter data. For Sonazoid, the square wave pulse at 2.5 MHz yielded the highest correlation ( r = - 0.72 ± 0.2 ). In conclusion, the real-time functionality of the customized interface has been verified, and the optimal parameters for utilizing Definity and Sonazoid for intracardiac SHAPE have been determined.
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14
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Kiessling F. US Microbubbles as Smart Sensors of Portal Venous Pressure. Radiology 2020; 298:112-113. [PMID: 33206005 DOI: 10.1148/radiol.2020203753] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Affiliation(s)
- Fabian Kiessling
- From the Institute for Experimental Molecular Imaging, Helmholtz-Institute for Biomedical Engineering, RWTH Aachen University, Forckenbeckstrasse 55, 52074 Aachen, Germany; and Fraunhofer MEVIS, Institute for Medical Image Computing, Aachen, Germany
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15
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Gupta I, Eisenbrey JR, Machado P, Stanczak M, Wessner CE, Shaw CM, Gummadi S, Fenkel JM, Tan A, Miller C, Parent J, Schultz S, Soulen MC, Sehgal CM, Wallace K, Forsberg F. Diagnosing Portal Hypertension with Noninvasive Subharmonic Pressure Estimates from a US Contrast Agent. Radiology 2020; 298:104-111. [PMID: 33201789 DOI: 10.1148/radiol.2020202677] [Citation(s) in RCA: 34] [Impact Index Per Article: 8.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Background The current standard for assessing the severity of portal hypertension is the invasive acquisition of hepatic venous pressure gradient (HVPG). A noninvasive US-based technique called subharmonic-aided pressure estimation (SHAPE) could reduce risk and enable routine acquisition of these pressure estimates. Purpose To compare quantitative SHAPE to HVPG measurements to diagnose portal hypertension in participants undergoing a transjugular liver biopsy. Materials and Methods This was a prospective cross-sectional trial conducted at two hospitals between April 2015 and March 2019 (ClinicalTrials.gov identifier, NCT02489045). This trial enrolled participants who were scheduled for transjugular liver biopsy. After standard-of-care transjugular liver biopsy and HVPG pressure measurements, participants received an infusion of a US contrast agent and saline. During infusion, SHAPE data were collected from a portal vein and a hepatic vein, and the difference was compared with HVPG measurements. Correlations between data sets were determined by using the Pearson correlation coefficient, and statistical significance between groups was determined by using the Student t test. Receiver operating characteristic analysis was performed to determine the sensitivity and specificity of SHAPE. Results A total of 125 participants (mean age ± standard deviation, 59 years ± 12; 80 men) with complete data were included. Participants at increased risk for variceal hemorrhage (HVPG ≥12 mm Hg) had a higher mean SHAPE gradient compared with participants with lower HVPGs (0.79 dB ± 2.53 vs -4.95 dB ± 3.44; P < .001), which is equivalent to a sensitivity of 90% (13 of 14; 95% CI: 88, 94) and a specificity of 80% (79 of 99; 95% CI: 76, 84). The SHAPE gradient between the portal and hepatic veins was in good overall agreement with the HVPG measurements (r = 0.68). Conclusion Subharmonic-aided pressure estimation is an accurate noninvasive technique for detecting clinically significant portal hypertension. © RSNA, 2020 Online supplemental material is available for this article. See also the editorial by Kiessling in this issue.
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Affiliation(s)
- Ipshita Gupta
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - John R Eisenbrey
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Priscilla Machado
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Maria Stanczak
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Corinne E Wessner
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Colette M Shaw
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Sriharsha Gummadi
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Jonathan M Fenkel
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Alison Tan
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Cynthia Miller
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Julia Parent
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Susan Schultz
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Michael C Soulen
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Chandra M Sehgal
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Kirk Wallace
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
| | - Flemming Forsberg
- From the Department of Radiology (I.G., J.R.E., P.M., M.S., C.E.W., C. M. Shaw, A.T., C.M., F.F.) and Department of Medicine, Division of Gastroenterology and Hepatology (J.M.F.), Thomas Jefferson University, 132 S 10th St, Philadelphia, PA 19107; School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, Pa (I.G.); Department of Surgery, Lankenau Medical Center, Wynnewood, Pa (S.G.); Department of Radiology, Hospital of the University of Pennsylvania, Philadelphia, Pa (S.S., M.C.S., C. M. Sehgal); and GE Global Research, Niskayuna, NY (K.W.)
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16
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Dave JK, Kulkarni SV, Pangaonkar PP, Stanczak M, McDonald ME, Cohen IS, Mehrotra P, Savage MP, Walinsky P, Ruggiero NJ, Fischman DL, Ogilby D, VanWhy C, Lombardi M, Forsberg F. Non-Invasive Intra-cardiac Pressure Measurements Using Subharmonic-Aided Pressure Estimation: Proof of Concept in Humans. ULTRASOUND IN MEDICINE & BIOLOGY 2017; 43:2718-2724. [PMID: 28807449 PMCID: PMC5605408 DOI: 10.1016/j.ultrasmedbio.2017.07.009] [Citation(s) in RCA: 27] [Impact Index Per Article: 3.9] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/08/2016] [Revised: 05/05/2017] [Accepted: 07/11/2017] [Indexed: 05/04/2023]
Abstract
This study evaluated the feasibility of employing non-invasive intra-cardiac pressure estimation using subharmonic signals from ultrasound contrast agents in humans. This institutional review board-approved proof-of-concept study included 15 consenting patients scheduled for left and right heart catheterization. During the catheterization procedure, Definity was infused intra-venously at 4-10 mL/min. Ultrasound scanning was performed with a Sonix RP using pulse inversion, three incident acoustic output levels and 2.5-MHz transmit frequency. Radiofrequency data were processed and subharmonic amplitudes were compared with the pressure catheter data. The correlation coefficient between subharmonic signals and pressure catheter data ranged from -0.3 to -0.9. For acquisitions with optimum acoustic output, pressure errors between the subharmonic technique and catheter were as low as 2.6 mmHg. However, automatically determining optimum acoustic output during scanning for each patient remains to be addressed before clinical applicability can be decided.
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Affiliation(s)
- Jaydev K Dave
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA.
| | - Sushmita V Kulkarni
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; College of Engineering, Drexel University, Philadelphia, Pennsylvania, USA
| | - Purva P Pangaonkar
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA; School of Biomedical Engineering, Science and Health Systems, Drexel University, Philadelphia, Pennsylvania, USA
| | - Maria Stanczak
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Maureen E McDonald
- Department of Radiologic Sciences, Jefferson College of Health Professions, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Ira S Cohen
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Praveen Mehrotra
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Michael P Savage
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Paul Walinsky
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Nicholas J Ruggiero
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - David L Fischman
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - David Ogilby
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Carolyn VanWhy
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Matthew Lombardi
- Division of Cardiology, Department of Medicine, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
| | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, Pennsylvania, USA
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17
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Gupta I, Eisenbrey J, Stanczak M, Sridharan A, Dave JK, Liu JB, Hazard C, Wang X, Wang P, Li H, Wallace K, Forsberg F. Effect of Pulse Shaping on Subharmonic Aided Pressure Estimation In Vitro and In Vivo. JOURNAL OF ULTRASOUND IN MEDICINE : OFFICIAL JOURNAL OF THE AMERICAN INSTITUTE OF ULTRASOUND IN MEDICINE 2017; 36:3-11. [PMID: 27943411 PMCID: PMC5191985 DOI: 10.7863/ultra.15.11106] [Citation(s) in RCA: 21] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/03/2015] [Accepted: 04/15/2016] [Indexed: 05/10/2023]
Abstract
OBJECTIVES Subharmonic imaging (SHI) is a technique that uses the nonlinear oscillations of microbubbles when exposed to ultrasound at high pressures transmitting at the fundamental frequency ie, fo and receiving at half the transmit frequency (ie, fo /2). Subharmonic aided pressure estimation (SHAPE) is based on the inverse relationship between the subharmonic amplitude of the microbubbles and the ambient pressure change. METHODS Eight waveforms with different envelopes were optimized with respect to acoustic power at which the SHAPE study is most sensitive. The study was run with four input transmit cycles, first in vitro and then in vivo in three canines to select the waveform that achieved the best sensitivity for detecting changes in portal pressures using SHAPE. A Logiq 9 scanner with a 4C curvi-linear array was used to acquire 2.5 MHz radio-frequency data. Scanning was performed in dual imaging mode with B-mode imaging at 4 MHz and a SHI contrast mode transmitting at 2.5 MHz and receiving at 1.25 MHz. Sonazoid, which is a lipid stabilized gas filled bubble of perfluorobutane, was used as the contrast agent in this study. RESULTS A linear decrease in subharmonic amplitude with increased pressure was observed for all waveforms (r from -0.77 to -0.93; P < .001) in vitro. There was a significantly higher correlation of the SHAPE gradient with changing pressures for the broadband pulses as compared to the narrowband pulses in both in vitro and in vivo results. The highest correlation was achieved with a Gaussian windowed binomial filtered square wave with an r-value of -0.95. One of the three canines was eliminated for technical reasons, while the other two produced very similar results to those obtained in vitro (r from -0.72 to -0.98; P <.01). The most consistent in vivo results were achieved with the Gaussian windowed binomial filtered square wave (r = -0.95 and -0.96). CONCLUSIONS Using this waveform is an improvement to the existing SHAPE technique (where a square wave was used) and should make SHAPE more sensitive for noninvasively determining portal hypertension.
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Affiliation(s)
- Ipshita Gupta
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
- School of Biomedical Engineering, Sciences and Health Systems, Drexel University, Philadelphia, PA 19104, USA
| | - John Eisenbrey
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Maria Stanczak
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Anush Sridharan
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
- Department of Electrical and Computer Engineering, Drexel University, Philadelphia, PA 19104, USA
| | - Jaydev K. Dave
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | - Ji-Bin Liu
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
| | | | - Xinghua Wang
- Department of Ultrasound, The 2nd Hospital of Shanxi Medical University, Taiyuan, Shanxi 030001, China
| | - Ping Wang
- Department of Ultrasound, The Affiliated Hospital of North Sichuan Medical College, Nanchong, Sichuan 637000, China
| | - Huiwen Li
- Department of Ultrasound, Erdos Center Hospital, Erdos, Inner Mongolia 017000, China
| | | | - Flemming Forsberg
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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18
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Shekhar H, Awuor I, Thomas K, Rychak JJ, Doyley MM. The delayed onset of subharmonic and ultraharmonic emissions from a phospholipid-shelled microbubble contrast agent. ULTRASOUND IN MEDICINE & BIOLOGY 2014; 40:727-38. [PMID: 24582298 PMCID: PMC3997117 DOI: 10.1016/j.ultrasmedbio.2014.01.002] [Citation(s) in RCA: 7] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/29/2013] [Revised: 11/26/2013] [Accepted: 01/06/2014] [Indexed: 05/08/2023]
Abstract
Characterizing the non-linear response of microbubble contrast agents is important for their efficacious use in imaging and therapy. In this article, we report that the subharmonic and ultraharmonic response of lipid-shelled microbubble contrast agents exhibits a strong temporal dependence. We characterized non-linear emissions from Targestar-p microbubbles (Targeson Inc., San Diego, CA, USA) periodically for 60 min, at 10 MHz excitation frequency. The results revealed a considerable increase in the subharmonic and ultraharmonic response (nearly 12-15 and 5-8 dB) after 5-10 min of agent preparation. However, the fundamental and the harmonic response remained almost unchanged in this period. During the next 50 min, the subharmonic, fundamental, ultraharmonic, and harmonic responses decreased steadily by 2-5 dB. The temporal changes in the non-linear behavior of the agent appeared to be primarily mediated by gas-exchange through the microbubble shell; temperature and prior acoustic excitation based mechanisms were ruled out. Further, there was no measurable change in the agent size distribution by static diffusion. We envisage that these findings will help obtain reproducible measurements from agent characterization, non-linear imaging, and fluid-pressure sensing. These findings also suggest the possibility for improving non-linear imaging by careful design of ultrasound contrast agents.
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Affiliation(s)
- Himanshu Shekhar
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
| | - Ivy Awuor
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA
| | | | - Joshua J Rychak
- Targeson Inc., San Diego, CA, USA; Department of Bioengineering, University of California at San Diego, La Jolla, CA, USA
| | - Marvin M Doyley
- Department of Electrical and Computer Engineering, University of Rochester, Rochester, NY, USA; Department of Biomedical Engineering, University of Rochester, Rochester, NY, USA.
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Paul S, Nahire R, Mallik S, Sarkar K. Encapsulated microbubbles and echogenic liposomes for contrast ultrasound imaging and targeted drug delivery. COMPUTATIONAL MECHANICS 2014; 53:413-435. [PMID: 26097272 PMCID: PMC4470369 DOI: 10.1007/s00466-013-0962-4] [Citation(s) in RCA: 30] [Impact Index Per Article: 3.0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/22/2023]
Abstract
Micron- to nanometer-sized ultrasound agents, like encapsulated microbubbles and echogenic liposomes, are being developed for diagnostic imaging and ultrasound mediated drug/gene delivery. This review provides an overview of the current state of the art of the mathematical models of the acoustic behavior of ultrasound contrast microbubbles. We also present a review of the in vitro experimental characterization of the acoustic properties of microbubble based contrast agents undertaken in our laboratory. The hierarchical two-pronged approach of modeling contrast agents we developed is demonstrated for a lipid coated (Sonazoid™) and a polymer shelled (poly D-L-lactic acid) contrast microbubbles. The acoustic and drug release properties of the newly developed echogenic liposomes are discussed for their use as simultaneous imaging and drug/gene delivery agents. Although echogenicity is conclusively demonstrated in experiments, its physical mechanisms remain uncertain. Addressing questions raised here will accelerate further development and eventual clinical approval of these novel technologies.
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Affiliation(s)
- Shirshendu Paul
- Department of Mechanical Engineering, University of Delaware, Newark DE 19716, USA
| | - Rahul Nahire
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo ND 58108, USA
| | - Sanku Mallik
- Department of Pharmaceutical Sciences, North Dakota State University, Fargo ND 58108, USA
| | - Kausik Sarkar
- Department of Mechanical and Aerospace Engineering, The George Washington University, Washington, DC 20052, USA
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20
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Dave JK, Halldorsdottir VG, Eisenbrey JR, Merton DA, Liu JB, Machado P, Zhao H, Park S, Dianis S, Chalek CL, Thomenius KE, Brown DB, Forsberg F. On the implementation of an automated acoustic output optimization algorithm for subharmonic aided pressure estimation. ULTRASONICS 2013; 53:880-8. [PMID: 23347593 PMCID: PMC3595343 DOI: 10.1016/j.ultras.2012.12.010] [Citation(s) in RCA: 27] [Impact Index Per Article: 2.5] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Received: 10/31/2012] [Revised: 12/20/2012] [Accepted: 12/20/2012] [Indexed: 05/04/2023]
Abstract
Incident acoustic output (IAO) dependent subharmonic signal amplitudes from ultrasound contrast agents can be categorized into occurrence, growth or saturation stages. Subharmonic aided pressure estimation (SHAPE) is a technique that utilizes growth stage subharmonic signal amplitudes for hydrostatic pressure estimation. In this study, we developed an automated IAO optimization algorithm to identify the IAO level eliciting growth stage subharmonic signals and also studied the effect of pulse length on SHAPE. This approach may help eliminate the problems of acquiring and analyzing the data offline at all IAO levels as was done in previous studies and thus, pave the way for real-time clinical pressure monitoring applications. The IAO optimization algorithm was implemented on a Logiq 9 (GE Healthcare, Milwaukee, WI) scanner interfaced with a computer. The optimization algorithm stepped the ultrasound scanner from 0% to 100% IAO. A logistic equation fitting function was applied with the criterion of minimum least squared error between the fitted subharmonic amplitudes and the measured subharmonic amplitudes as a function of the IAO levels and the optimum IAO level was chosen corresponding to the inflection point calculated from the fitted data. The efficacy of the optimum IAO level was investigated for in vivo SHAPE to monitor portal vein (PV) pressures in 5 canines and was compared with the performance of IAO levels, below and above the optimum IAO level, for 4, 8 and 16 transmit cycles. The canines received a continuous infusion of Sonazoid microbubbles (1.5 μl/kg/min; GE Healthcare, Oslo, Norway). PV pressures were obtained using a surgically introduced pressure catheter (Millar Instruments, Inc., Houston, TX) and were recorded before and after increasing PV pressures. The experiments showed that optimum IAO levels for SHAPE in the canines ranged from 6% to 40%. The best correlation between changes in PV pressures and in subharmonic amplitudes (r=-0.76; p=0.24), and between the absolute PV pressures and the subharmonic amplitudes (r=-0.89; p<0.01) were obtained for the optimized IAO and 4 transmit cycles. Only for the optimized IAO and 4 transmit cycles did the subharmonic amplitudes differ significantly (p<0.01) before and after increasing PV pressures. A new algorithm to identify optimum IAO levels for SHAPE has been developed and validated with the best results being obtained for 4 transmit cycles. The work presented in this study may pave the way for real-time clinical applications of estimating pressures using the subharmonic signals from ultrasound contrast agents.
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Affiliation(s)
- J K Dave
- Department of Radiology, Thomas Jefferson University, Philadelphia, PA 19107, USA
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